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The aim of this report was to evaluate the efficacy of bacteriophage therapy and its potential to be applied in parts of the developed world and West Africa. Based on obtained information about past applications of phage in Georgia and Poland, current applications in the Western world and possible applications in West Africa, the writer has been able to draw conclusions from observable similarities within these three aspects of the report. This chapter provides further evaluation and concluding remarks about bacteriophage therapy.
6.1 FURTHER EVALUATION
Bacteriophage therapy appears to be an exciting new form of therapy that could be widely applied for a broad range of bacterial infectious diseases, especially in cases where the causative bacteria are proven to be antibiotic resistant. Notwithstanding, there have been a few publications criticising the potential of bacteriophages to replace antibiotics. One of such publications stated that pathogenic bacteria have a problem of developing resistance to lytic bacteriophages (Mathur et al., 2003). Although this is a common cause for concern, Petty et al. (2007) affirm that bacteriophages generally tend to evolve along with mutant bacteria in the natural environment. Resistance can also be avoided by using a cocktail of two or more phages, so that at least one phage remains effective in the presence of mutant bacteria, as demonstrated by Smith and colleagues (cited by Barrow & Soothill, 1997). This has been validated by successful clinical trials carried out by Georgian scientists and some recently established western companies, as discussed in chapters 2 and 4.
In addition, the action of bacterial resistance to bacteriophages, usually by mutation of phage receptors, tends to reduce the virulence of bacteria (Skurnik & Strauch, 2006). The bacteria in question become ineffective pathogens and thus more susceptible to actions of the immune system. A further advantage of the presence of avirulent bacteria, due to phage resistance, is the possibility of applying these bacteria in the production of vaccines. According to a study carried out by Capparelli et al. (2010), selecting phage resistant mutants for vaccine production provides a new approach for the application of bacteriophages in the prevention of bacterial diseases.
The notion stated by Mathur et al. (2003), that phage lysis of bacteria could result in the release of endotoxins which may lead to deleterious side effects or even death is unjustifiable because such has not been proven in previous clinical studies. The release of endotoxins is common in the use of antibiotics, leading to such side effects as yeast infection and diarrhoea because normal bacterial flora are also affected (Pirisi, 2000). Nevertheless, the broad spectrum activity of antibiotics serves as an advantage over bacteriophages, because of the strain specificity of phages. However, genetic modifications can be potentially carried out on phage structures to increase the host range. Moreover, the problem of toxin enhancing or toxigenic gene transfer from phages to bacteria during transduction can be overcome if adequate care is taken to remove such genes from phages in vitro (Alisky et al., 1998), also only suitable phages without the ability to carry out specialised or generalised transduction should be selected or mutant phages should be genetically constructed to act against such (Matsuzaki et al., 2005).
There were many issues with the clinical studies carried out by Eastern European researchers in the 20th century, many of them did not involve the use of proper control or placebo groups, probably because there was a lack of understanding of phage biology and scientific protocols were still at an early stage. The results obtained were probably biased results because they were based on non-controlled experiments. In spite of this, phage therapy seemed highly effective, particularly for ââ‚¬Ëœlocalised diseasesââ‚¬â„¢, such as furunculosis, but the potential of phages against systemic diseases like bactaeremia is yet to be evaluated or confirmed.
Researchers in the West have learned from the past mistakes of the East and are currently leading the way for phage research and placebo controlled clinical trials. Companies such as Biocontrol Ltd, Intralytix and Novolytics are at the forefront of phage research in the UK and US. Some of these companies, e.g. Intralytix, are collaborating with the Eliava Institute in Georgia to reproduce some of the instituteââ‚¬â„¢s successful products and joining forces in research endeavours. Others, such as Biocontrol Ltd, have conducted or are conducting double blinded placebo controlled human clinical trials to test the efficacy of bacteriophages in therapy. There are yet others, for example Phico therapeutics, which have chosen to use phage as a vehicle for novel antibiotics, in the place of live phages in therapy. These many endeavours by several western companies may very well be needed to push large pharmaceuticals into the rush for alternative therapy.
As with other new therapeutics, there is the need to go through regulatory approval and proper protection of intellectual property. Although a small number of patents have been acquired, by some western companies e.g. Intralytix, and one or two FDA approvals have been obtained, also by western companies, it is not guaranteed that any more approvals or patents will be obtained in the near future. This does not provide an encouraging scenario for large pharmaceuticals, since a lack of IP cover would result in huge payouts to licensing companies and a delay or denial of FDA or MHRA approval, would almost certainly result in devastating financial loss.
Phage therapy could also be potentially effective in developing countries, where antibiotics are severely abused and where the disease burden is very high due to inadequate health facilities and many other reasons. There is an urgent need for novel antibacterials in such countries. If phage therapy is implemented in hospitals, it could help to not only reduce the amount of money spent yearly on treating patients, it could also reduce the duration of treatment and have overall economic advantages to the country involved.
Overall, the main observable similarity from the three aspects covered in this report, is the promise of effective eradication or reduction in the occurrence of antibiotic resistant diseases through the use of bacteriophages as an alternative to antibiotics.
There is compelling evidence of the great potential of the bacteriophage as a therapeutic agent against bacterial infections. However, it may take a while for individuals to fully accept phages over antibiotics as the new form of treatment. Although bacteriophages were discovered a good while before antibiotics, the latter have been in use for a much longer period of time and have thus been etched into the minds of people as the first point of treatment. People would need to be advised on the need for a new form of therapy and phage therapy could then be made readily available. Phage therapy could also be introduced as a special treatment for life threatening drug resistant diseases. Overall, phage therapy seems to have a promising future in both the developed and developing world.